The state of Oklahoma is served by the following area codes:
Area codes 705, 249, and 683 are telephone area codes in the North American Numbering Plan (NANP) for most of northeastern and central Ontario in Canada. Area code 705 was created in a 1956 area code split from portions of the 613 and 519 numbering plan areas. After a reduction in geographic coverage in 1962, the numbering plan area was assigned a second area code, 249, in 2011 to form an overlay numbering plan. A third area code, 683, was added in June 2022.
Area codes 905, 289, 365, and 742 are telephone area codes in the North American Numbering Plan (NANP) for the Golden Horseshoe region that surrounds Lake Ontario in Southern Ontario, Canada. The numbering plan area (NPA) comprises (clockwise) the Niagara Peninsula, the city of Hamilton, the regional municipalities of Halton, Peel, York, Durham, and parts of Northumberland County, but excludes the City of Toronto.
Area codes 514, 438, and 263 are telephone area codes of the North American Numbering Plan (NANP) for Montreal and most of its on-island suburbs, specifically the Island of Montreal and Île Perrot in the Canadian province of Quebec.
Area code 781 and 339 are telephone area codes in the North American Numbering Plan for the U.S. state of Massachusetts. The numbering plan area consists of Boston’s inner suburbs, known as the Route 128 corridor, and some outer suburbs, especially in the South Shore region. It was created as in an area code split of area code 617 on September 1, 1997. Use of 781 became mandatory February 1, 1998. Area code 339 is an overlay complex code for the same service area, activated on May 2, 2001. Since then, ten-digit dialing has been mandatory.
Area codes 208 and 986 are telephone area codes in the North American Numbering Plan for all of Idaho. Area code 208 is one of the 86 original area codes created by the American Telephone and Telegraph Company (AT&T) in 1947, and was Idaho's sole area code for seventy years. In 2017, 986 was added as a second area code to the same numbering plan area by creating an overlay complex.
Area code 250 is a telephone area code in the North American Numbering Plan (NANP) for the Canadian province of British Columbia outside the Lower Mainland, including Vancouver Island–home to the provincial capital, Victoria–and the province's Interior region. In addition, the numbering plan area extends into the United States community of Hyder, Alaska, located along the Canada–United States border near the town of Stewart. The incumbent local exchange carriers that service the area code are Telus, Northwestel, and CityWest in the city of Prince Rupert.
Area codes 204, 431, and 584 are telephone area codes in the North American Numbering Plan (NANP) for the Canadian province of Manitoba. Area code 204 is one of the nine original North American area codes assigned to Canada in 1947. Area codes 431 and 584 were assigned to the same numbering plan area (NPA) in 2012 and 2022, respectively, forming an overlay complex.
Area codes 778, 236, and 672 are telephone area codes in the North American Numbering Plan (NANP) for the Canadian province of British Columbia. They form an overlay complex with area code 604, which serves only a small southwestern section, the Lower Mainland, of the province, and area code 250, which serves the rest of the province.
Area codes 306, 639, and 474 are telephone area codes in the North American Numbering Plan (NANP) for the entire Canadian province of Saskatchewan. Area code 306 is one of the original North American area codes assigned in 1947. Area codes 639 and 474 were added to the numbering plan area in creation of an overlay complex for the entire province in 2013 and 2021, respectively. The incumbent local exchange carrier is SaskTel.
Area code 780 is a telephone area code in the North American Numbering Plan (NANP) for the Canadian province of Alberta. The numbering plan area comprises the northern two thirds of the province, including the Edmonton area. The area code was established in 1999 in a split of area code 403, which had served the entire province since the establishment of the original North American area codes in 1947. The numbering plan area is also served by area codes 587, 825, and 368, which form a complex overlay for all of Alberta.
Area code 604 is a telephone area code in the North American Numbering Plan for southwestern British Columbia, Canada. The numbering plan area comprises the Metro Vancouver, Sunshine Coast, Howe Sound / Sea to Sky Corridor, Fraser Valley and the lower Fraser Canyon regions. The major city is Vancouver. The area code is one of the nine original North American area codes assigned to Canada in 1947.
Area codes 573 and 235 are telephone area codes in the North American Numbering Plan (NANP) for most of the eastern half of the U.S. state of Missouri outside the immediate St. Louis area, including the state capital of Jefferson City, as well as Columbia, Cape Girardeau, Hannibal, Rolla, and Sikeston. The largest cities are Columbia, home to the University of Missouri, and Jefferson City, the state capital.The numbering plan area (NPA) extends across half of the width of the state, with the northeastern tip near the northeastern corner of the state, the Lake of the Ozarks at the western tip and Doniphan as the southwestern tip. They also serves all of southeastern Missouri and areas adjacent to the Mississippi River. 573 was created on January 7, 1996, in a split of area code 314, which was limited to the St. Louis metropolitan area in Missouri, and 235 was added on March 24, 2024 as part of an overlay complex.
Area codes 860 and 959 are telephone area codes in the North American Numbering Plan in the U.S. state of Connecticut. They are arranged in an overlay plan that covers most of the state, except its southwest, which uses area codes 203 and 475.
Area codes 303, 720 and 983 are telephone area codes in the North American Numbering Plan for the north-central portion of the U.S. state of Colorado. The numbering plan area comprises Denver and Boulder, as well as their surrounding suburbs, including Lakewood, Littleton, Longmont, Broomfield, Aurora, and Castle Rock. Area code 303 is the original area code, while area codes 720 and 983 were added to form an overlay complex for the area, meaning that the same geographic service area is served by all area codes and that ten-digit dialing is required for all calls made within the service area.
Area codes 405 and 572 serve the central part of the U.S. state of Oklahoma. They cover Oklahoma City and most of its suburbs, including Edmond, El Reno, Norman, Stillwater, Shawnee, Chickasha, Tuttle, Moore, and Guthrie.
Area codes 816 and 975 are telephone area codes in the North American Numbering Plan (NANP) for most of the Missouri side of the Kansas City metropolitan area, the St. Joseph area, and all or part of 15 surrounding counties in northwestern Missouri. The numbering plan area originally comprised most of the northern and western two-thirds of the state, bordering with Arkansas, Illinois, Iowa, Kansas, Nebraska, and Oklahoma, but has been reduced to a ribbon bordering Kansas. 816 is one of the original 86 area codes created in 1947. The numbering plan area was converted to an overlay complex with area code 975 in 2023.
Area codes 918 and 539 are telephone area codes serving Tulsa and northeast Oklahoma. Besides Tulsa, these area codes cover cities such as Bartlesville, Broken Arrow, Claremore, Gore, Jenks, McAlester, Muskogee, Okmulgee, Pryor, Sapulpa, Tahlequah, and northeastern Oklahoma.
Area code 580 serves most of southern and western Oklahoma, including Ada, Boise City, Lawton, Enid, Fairview, Ponca City, Altus, Frederick, Weatherford, Guymon, Durant, and Ardmore.
Area codes 587, 825, and 368 are telephone area codes in the North American Numbering Plan (NANP) for the entire Canadian province of Alberta. They form an overlay with area code 403 of southern Alberta, and northern Alberta's 780. The complex overlay involving a total of five area codes in Alberta mandated ten-digit dialing throughout the province.